summaryrefslogtreecommitdiffstats
path: root/strtod.c
AgeCommit message (Collapse)Author
2015-10-30Move all core-functionality to subsurface-coreGravatar Tomaz Canabrava
And adapt a new CMakeLists.txt file for it. On the way I've also found out that we where double-compilling a few files. I've also set the subsurface-core as a include_path but that was just to reduce the noise on this commit, since I plan to remove it from the include path to make it obligatory to specify something like include "subsurface-core/dive.h" for the header files. Since the app is growing quite a bit we ended up having a few different files with almost same name that did similar things, I want to kill that (for instance Dive.h, dive.h, PrintDive.h and such). Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-02-27Massive automated whitespace cleanupGravatar Dirk Hohndel
I know everyone will hate it. Go ahead. Complain. Call me names. At least now things are consistent and reproducible. If you want changes, have your complaint come with a patch to scripts/whitespace.pl so that we can automate it. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-02-16micro-optimisation: avoid division in main strtod() loopGravatar Linus Torvalds
Division is expensive, so replace it with multiplication instead. But don't multiply by 0.1 (inexact in floating point), multiply by 10 and then do one division at the end. Make sure the final division is at the very end, so that the result isn't immediately used. That allow the division to overlap with the function return overhead, hiding it further. This is silly, but while thinking about different file formats and doing profiling of loading big files, it turned out that "strtod_flags()" actually showed up in profiles. Not very high, but at more than 1%. This makes the common case (no exponent) use only addition and multiplication until the very end, and makes the division be the very last thing it does, which minimizes the data dependencies on the division. For my stupid test-case, it cut the cost of strtod_flags() in half according to the profile. The half a percent speedup on loading time isn't really noticeable or even measurable outside of profiling startup costs, but rather than carry this along in my tree or just throw it away, I'm sending it out to see if anybody cares. Note that we could avoid the final division by instead multiplying "decimal" with 0.1 rather than multiplying by 10 (and switching the sign test over), but that's a fundamentally inexact operation in binary floatig point, so doing the "multiply by tens for decimals" ends up keeping everything exact as long as possible. For our use, we probably really don't care, but whatever. End result: this should not only speed things up immeasurably, it *might* also make things more precise at a level that we really don't care about :^p I'm really selling this piece of crap, aren't I? [Dirk Hohndel: sorry - had to pull the full email into the commit message this is so good, you couldn't make it up] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-01-08const'ify our strtod() helper functionsGravatar Linus Torvalds
The C library doesn't use const char pointers for legacy reasons (and because you *can* modify the string the end pointer points to), but let's do it in our internal implementation just because it's a nice guarantee to have. We actually used to have a non-const end pointer and replace a decimal comma with a decimal dot, but that was because we didn't have the fancy "allow commas" flags. So by using our own strtod_flags() function, we can now keep all the strings we parse read-only rather than modify them as we parse them. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-01-02Make our 'ascii_strtod()' helper more genericGravatar Linus Torvalds
We'll want to do sane parsing of strings, but the C library makes it hard to handle user input sanely and the Qt toDouble() function interface was designed by a retarded chipmunk. So just extend our existing hacky "ascii_strtod()" to allow a more generic interface. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>